Cancer is the second leading cause of death among children, but little is known on the etiology of childhood cancers. The majority of previous attempts to link childhood cancer to pesticides have relied upon parental interview or sources such as birth or death records, making results potentially subject to biases of recall or information, and few studies have had adequate power to study specific cancer subtypes or had an exposure assessment that was able to assess exposures to specific pesticides. We propose a large case-control study of California children diagnosed with certain cancers (acute myeloid leukemia, acute lymphoblastic leukemia, non Hodgkin lymphoma, astrocytoma, primitive neuroectodermal tumors, Wilms tumor, soft tissue sarcomas) and population-based controls. Cases and controls will be taken from the ongoing population-based Air Pollution and Childhood Cancers (APCC) study, in which we linked cancer cases, identified from the California Cancer Registry to birth certificates and selected controls at random from California birth records. The proposed study will include approximately 9000 cases and 90000 controls. Exposure to pesticides will be assessed using our geographic pesticide exposure assessment tool (GRAPES) that utilizes the unique California Pesticide Use Report system, in combination with agricultural land-use maps, to derive record-based estimates of residential exposures to specific pesticides. The GRAPES system will estimate trimester-specific pregnancy and early childhood (<1 year of age) exposures to pesticides, allowing us to identify critical time windows of exposure to toxins in gestational development. Our focus will be the carcinogenic effects of 23 agents which have been identified as likely or probable carcinogens by the US EPA and which are among the most commonly applied pesticides in California. This proposal presents an exciting opportunity to identify specific cancer-pesticide links, with the possibility of informing policy on pesticide regulation and encouraging research on therapeutic and preventive strategies. PUBLIC HEALTH RELEVANCE: This project proposes to evaluate the carcinogenicity of specific pesticides in relation to certain childhood cancers. We will determine pesticide exposures using our geographic pesticide exposure assessment tool (GRAPES) that integrates pesticide application information from the unique California Pesticide Use Report system with agricultural land-use maps, to pinpoint residential exposures to specific pesticides.